In general, laser cutting machines include a workpiece support and a laser cutting head configured to focus a laser beam onto the workpiece. The laser cutting head is supported by a motion unit and can be displaced along the motion unit.
Typically, the motion unit of such laser cutting machines is arranged so as to be movable along a long side of the workpiece support, i.e. along the longer side of a rectangular plate-shaped workpiece, in what is known as a longitudinal laser cutting machine. U.S. Pat. No. 9,044,826 describes a longitudinal laser cutting machine in which the motion unit is supported from below, while International Patent Application Publication No. WO 1999/028798 describes a longitudinal laser cutting machine having a hanging motion unit, i.e. a motion unit that is supported from above. U.S. Pat. No. 5,402,691 describes a longitudinal laser cutting machine having a hanging motion unit that is suspended, at intermediate locations, from two top beams that extend along a long direction of a machine base and an asymmetrical center pull drive system that is used to move the motion unit along the top beams. However, in the longitudinal laser cutting machine provided in U.S. Pat. No. 5,402,691, large deflections of the motion unit between the supports occur because forces applied to the motion unit structure between the supports are comprised of inertial forces and X drive pull forces. In other laser cutting machines having a hanging motion unit configuration (such as those shown in U.S. Pat. No. 6,140,606, European Patent Document No. EP0927597A1, and Chinese Patent Document Nos. CN101301724A, CN105290612A, and CN203031122U), the motion unit is relatively short, but its high mass moves perpendicular to the direction in which the machine frame is most rigid (i.e., the motion unit moves in the weak direction of the machine) and thereby limits the dynamics and productivity of the machine.
As an alternative to longitudinal laser cutting machines, transversal laser cutting machines can be provided in which a motion unit is arranged so as to be movable along a short side of the workpiece support, i.e. along the shorter side of a rectangular plate-shaped workpiece. As compared to longitudinal laser cutting machines, conventional transversal laser cutting machines provide a number of advantages. For example, conventional transversal laser cutting machines provide improved access to the workpiece, the ability to load larger workpieces directly onto the machine, and improved visibility of the cutting process. Furthermore, conventional transversal laser cutting machines provide for a higher mass motion unit to be moved along the shorter side of the workpiece support while a lower mass laser cutting head is moved along the longer side of the workpiece support. However, as a result of the need for a longer motion unit that extends across the long side of the workpiece support (and therefore has a relatively greater mass), transversal laser cutting machines exhibit certain limitations because inertial forces resulting from movement of the motion unit can cause large deflections at the center of the motion unit. In order to improve machine dynamics and productivity in transversal laser cutting machines, an additional motion axis for the cutting head can be included to allow the cutting head to be moved in parallel with the motion unit. This is shown, for example, in U.S. Pat. Nos. 6,825,439 and 6,835,912.